1. Field of the Invention
The present invention relates generally to radio frequency (RF) networks, and more particularly to a PIN diode network for multiband RF coupling.
2. Description of the Prior Art
PIN diodes are commonly used for RF switching. The PIN diode is a semiconductor device with heavily doped p-type and n-type regions separated by an intrinsic region. When forward biased or “on,” the PIN diode behaves as a variable resistor. When a PIN diode is zero or reverse biased (off, the PIN diode appears as a parallel plate capacitor, with “stray” capacitance essentially independent of bias voltage.
PIN diodes are available in a variety of form factors and performance attributes. Generally, one performance attribute that drives cost of the PIN diode is stray capacitance. At a given operating frequency, a PIN diode with relatively lower stray capacitance is typically more expensive than a PIN diode with higher stray capacitance.
A limitation with PIN diodes in RF switching applications is reduced isolation due to the stray capacitance of the PIN diode when at zero or reverse bias.